Field of the Invention
The invention relates in general to a touch control system, and more particularly, to a technology for correcting sensing results of a touch panel.
Description of the Related Art
Operating interfaces of recent electronic products have become increasingly user-friendly and intuitive with the progressing technology. For example, through a touch screen, a user can directly interact with applications and input messages/texts/patterns with fingers or a stylus, thus eliminating complexities associated with other input devices such as a keyboard or buttons. In practice, a touch screen usually comprises a touch panel and a display disposed at the back of the touch panel. According to a touch position on the touch panel and a currently displayed image on the display, an electronic device determines an intention of the touch to execute corresponding operations.
Existing capacitive touch sensing techniques can be roughly categorized into self-capacitive and mutual-capacitive types. Compared to mutual-capacitive touch panels, self-capacitive touch panels can be implemented through a single-layer electrode with a simpler manufacturing process and lower costs, and thus prevail in many entry-level electronic products.
FIG. 1 is an exemplary electrode configuration of a self-capacitive touch panel. A sensing region 100 represented by a dotted frame includes a plurality of triangular electrodes in a staggered arrangement along the X direction. Each of the electrodes may be connected to a sensor (not shown) that detects a capacitance change of the connected electrode. The capacitance changes detected by the sensors are forwarded to a controller (not shown), which accordingly determines a user touch position. Generally known to one person skilled in the art, as limited by the sensing accuracy (related to factors such as the number/shape of electrodes and the number of sensors) of the touch panel, a difference inevitably exists between an actual user touch position and a touch position determined by an electronic apparatus. Taking the electrode shape/configuration in FIG. 1 for example, when a user touches the left or right border of the sensing region 100, the Y coordinate in a sensing result frequently contains a large error. Given an excessively large error in the sensing result, it is expected that the electronic apparatus likely misjudges a touch intention of the user to lead to an unintended operation. Therefore, there is a need for a correction mechanism.
In a current correction method, a look-up table (LUT) is first established. The LUT stores various possible sensing results and corresponding correction results. In a situation where a sensing result is two-dimensional X/Y coordinates, if there are an N number of X/Y combinations for a sensing result, the LUT needs to store a total of N sets of non-corrected two-dimensional coordinates (X/Y) and corrected two-dimensional coordinates (X″/Y″), meaning that such approach suffers from a drawback of requiring a massive memory space for the LUT.